Credit

Caption

Archaeological conservation. Electrolytic treatment of a child's iron death mask found on an archaeological dig. Conservation of such objects involves preventing further damage, such as rust, without altering its structure. Metal objects are treated by electrolysis. This is the application of an electric current through an object that has been placed in a solution that conducts electricity. In the case of iron, a weak acid is used which results in the formation of a stable complex between chloride ions and iron, causing the rust to dissolve.